How can you spot the difference between G maderense and G palmatum?

I have grown for about 6 years what I thought was G maderense. The original plant is about 3' tall but it seeds about happily and all the babies I have potted up have grown on really well and quickly and flowered in the same year I have potted them up. Now I am wondering if in fact it is Geranium palmatum because it has survived outside with no protection, even getting through last winter which was awful. It is in a west facing border in decent soil. The flowers have a slightly darker centre but the stems aren't brown, which I am led to believe they should be.

Answers

My RHS book tells me that G.maderense takes a while to flower, then dies. Also, it is not hardy in the UK, while G. palmatum can be - in sheltered positions in the South of the UK, and it's evergreen as well. It certainly sounds as though you have G. palmatum there!

Thank you for taking the trouble to respond. I think you are right, and I had pretty well decided it was G palmatum, especially because I knew or thought I knew that G maderense was monocarpic. What held me back is that I bought it from a very knowledgeable local lady, so couldn't quite believe she would have got it wrong! Thank you again.